User cooperation has been of growing interest recently where extra spatial diversity can be achieved by allowing users to relay the messages of each other to the destination. Conventionally, user cooperation has been proposed for improving the capacity of a cellular network and has been closely related to transmission in a relay channel. Since then, on top of the idea of a general relay network, several efficient cooperative protocols have developed. For instance, multiple cooperating users with multiple antennas have been considered; however, all of the existing systems focus only on the performance and operation of fixed source and destination pairs without considering the higher-level system perspective. For instance, the effects of user scheduling have not been considered. In addition, the conventional relaying protocols often require dedicated relaying timeslots, potentially incurring a spectral loss.
Accordingly, it would be desirable to explore different scheduling strategies on user cooperation for a conventional cellular network to form more optimal strategies. The above-described background concerning deficiencies of current designs for user cooperation is merely intended to provide an overview of some of the problems of today's designs, and is not intended to be exhaustive. Other problems with the state of the art and corresponding benefits of the invention may become further apparent upon review of the following description of various non-limiting embodiments.